Spark plug



L. MCK. FIELD April 21, 1953 SPARK PLUG Filed May 21, 1951 ATTORNEY f Patented Apr. 2l, `1953 i1 UNITED STATES PATENT OFFICE 2,635,598v SPARK PLUG Lloyd McKinsey Field,v NewgLondon', Ohio; Floyde Josephine Field Karcher; Pueblo, Color, execu trix of'saidLlydMcKinsey Field; deceased, as; signor, by mesne assignments; tofAndIeW: Re Cochrane,- Bttsburgh, Pa., trustee 'l'hisl invention relates` tov an improved; `spark 'pingof thegeneral type having a valve-controlled passage which a'dmts;.a fluid r to the. associated enginecylinder upon each. intaliie stroke ot" the piston: In'one example' of this typeof.,l plug.' theA valvev ofjtlie' fluidk admitting passage is formed hya'lowerpositive' electrodesection, and to" limit the inward opening, movement ofthis valve the negativeelctrode is utilized as a stop. This, however; results ina severe hammering action of tlie'valvel uponthe negative electrode and' necesisitatesithat' the; latter be of unusually rugged frm.

Onezobject'of'the' present .invention is to provide'animproved construction inwhich the openingmovements'of' the valve are linited'by a port1'on'-of"the` plugf'insulator instead of by the negative electrode.

-In attainingthe'aboveobject, the upper end of' theJ lowery electrodev section is provided' with a valve-headwithin arecessin the insulator and said valve head simply strikes thebottom of this recess v to limit VaIveppening'; anda further ob- :lectA is1to provide an improved insulator which facilitates manufacture' with therequired. recess and'facilitatesassembly'with the valve head in Said recess.V

The-insulator is fof sectional construction with the Lfval'vehead-receiving-recess formed in one of its sections', anda further object isV to so secure' theinsulatorsections together that "therewill be no,A danger of current4 leakageY or'- compression: leakage between. them.

Anotherobject' isto' make novel provision for conducting thewcurrent to the-lower electrode section from al iixedupper electrode-section acting'a's abinding post for the spark plug wire.

Yet another object is to provide a, simple yet durable construction which may be expeditiously manufactured andv marketed at a reasonable price.'H

With the above and other-objects inview that willV become apparent'as the nature of the in-r vention: is,` betterl understood, theA same consists inthe novelform, combination and arrangement of. parts hereinaftermore fully described, shown in. the accompanying f drawing, and claimed.

In the drawing:

Figure 1 is a- Vertical' longitudinal sectional View showing one form. of the improved plug, r Figure: 2.is1aflower`end view of the upper insulator'sectionof Figure 1,

' FigureiS is' an upper'endview ofthe lower insulator section of Figure 1,

"-Figurei i'sf-'aJ perspectiveview 'of the'conductorv which extends between the" upper AandA lowerA seetions `of the positive'electrode; and' l l Figure 5' is'a'view similar toFigurelbutpart# l'y in side elevation,` showing asecond*l form' on construction'.V

cured to the'lower end Vof the shell fand'projects" inwardly therefrom.

The insulator shown in-Figures 1, 2`, and 'Bicomh prises an upper section I Iand a lower sectionv I2; while that shown'in Figure 5v comprises "anupper' section IIE a lower sectionr I2@ and anu inter` mediate `section I3.- The upper insulatorseetion; in each case', carriesaxed upper-positive-electxjodeA SectionY III` having a longitudinal' port I5 from end-to-end, while thelowerfsection"carries aI lowerreciprocable center` electrode section IIi;v

said Section lfhaving" a; valve head I1' integral with or' suitably secured to'itsupperend. 'Ihe peripheryof the electrode section I6; at thelower end portion of the-latten isy radially spaced-from the inner-'end of the negativeelectrode IIl to provide a sparkh gap.

I Theupper rinsulatc'ir section IIv ofFl'gurelis' provided aI-rits'lower` end withl a` head I 8 received in theshell 6; In the lowerfendfof tliisfhead'IS; there is a central downwardly'fopening recess` I9 which receives the 'valve'fhead I'I of theI lower. electrode Section I6. Al central port 20 inthe-l insulator section II communicates at its lower end with therece'ss I9, andthecorner-21'at1 the juncture ofy said'port and recess forms a'seat `for the-valve head I'i. Thevlower endV of the upper electrode section III is suitablysecuredin-the'upper portion ofy theport-ZU.

The lower insulator section I2"of 'Figure'k 1 is provided at itsY upper end with a head '22 which abuts 'the head vI8 `of the upper section Il. The

Y two'headsA I3'and122 are-clamped inthe shellG 'I'he abutting ends of the two heads I8 and 22 are provided with concentric tightly intermeshing ribs 26 and 21 respectively. The distance from the recess I9 to the periphery of the insulator, measured along an undulating line following the surfaces of the ribs 26 and 21, is considerably greater than the length of a straight radial line from said recess to said periphery. Thus, the distance which a leaking current or leaking compression would have to travel is materially increased by the intermeshed rib construction. Therefore, there is no danger of faulty plug and engine operation due to current or compression leakage between the heads I8 and 22, even if nothing but contact of the two ribbed heads is relied upon to effect the required seal, whereas mere contact of two flat surfaces on said heads might permit some leakage, due to the shortened path along which such leakage might travel. The construction under considerationv is particularly advantageous with present day high-compression engines in which the high compression not only seeks to escape at every possible point, but in which said high compression sets up great resistance to the jumping of the spark and the high tension current will therefore take any possible course of less resistance.

To establish an electrical connection between the upper electrode section I4 and the lower section I6, at least at the moments when the plug must fire, a conductor 28 is provided in the port 20. In the present disclosure, this conductor is a zigzag length yof ne wire having a horizontal coil or ring 29 at its upper end and a similar coil or ring 30 at its lower end. These rings contact with the electrode section I4 and the valve head I'I. respectively, Vwhen said valve head is closed againstv the seat 2|. This valve head, in the present disclosure, is conical with its apex portion extending into the port 28, and the ring 3U of the conductor 28 surrounds said apex portion and thus remains in proper relation with the valve head. The reciprocatory movements of the valve however are in no sense dependent upon the conductor 28, valve opening and closing being caused entirely by the minus and plus pressure in the engine cylinder, respectively.

In Figure 5, the heads I8El and 22a of the insulator sections I In and |22t are provided with flat inner ends 2&3a and 21a, respectively. The intermediate insulator section I3 is a fiat-sided ring, the sides of Iwhich abut the surfaces 2lia and 21a, respectively. Thecentral opening I9a of this ringiprovides a recess receiving the valve head I1 f the lower electrode section I6. 'I'he insulator section I3 may be of a softer insulating material than the sections I|EIL and I2u and may thus have some yieldable compressibility, to act as a gasket and thus prevent compression and current leakage. However, a sealing cement could of course be used between the insulator sections if desired. It will also be understood upon an inspection of Figure that a recess comparable with the recess |92 illustrated, may be formed in the upper side of the head 22a with the valve head I1 positionable therein and that the intermediate insulator section I3 of the plug may have the wall of the central opening thereof dimensioned to constitute a valve seat for engagement with the valve I'I.

The grooves 25, seat 2|, ports 2|)a and 24a, and conductor 28aL of Figure 5, correspond to the grooves 25, seat 2 I, ports 28 and 24, and conductor 28 ofgFigllre 1.

During each intake stroke of an engine equipped with the improved plug, iluid enters the cylinder through the port I5, port or 20a, recess I9 or |95, grooves 25 or 25a, and port 24 or 24a, and this fluid performs a cooling function adding to the life of the plug. Upon each compression stroke, the lower electrode section I6 is forced upwardly and the valve head I'I seats against the seat 2| or 2|, preventing escape of compression. Whenever the head I1 is seated, the conductor 28 or 28a establishes an electrical connection between the upper electrode section I4 and the lower electrode section I6, providing for conduction of the high tension current to the section I6 at the proper time.

As a further means to eliminate any possible current leakage, it is also intended that the upper end lower insulator sections II and I2 have registering or alined annular grooves or channels opening at the meeting ends of the insulator sections and concentric with the longitudinal axis of such sections for the reception of a mica or other insulation cuif or cylinder. It will also be observed that the shell holding the insulator is of two-piece construction whereby upon removal of the ring nut 8 all parts of the plug may be removed from the shell 6 for the replacement of any part thereof.

From the foregoing, it will be seen that novel and advantageous provision has been made for attaining the desired ends, and while preferences have been disclosed, variations may of course be made within the scope of the invention as claimed. For example, while the valve head I1 is shown of conical formation, it could well be of other configurations to accomplish the desired purpose. Further, it will be understood that the conductor 28 or 28a may assume other shapes, its function being merely to establish a current ow path between the upper electrode section I4 and the lower central electrode section I6.

I claim:

i l. A spark plug comprising .a central insulator having an internal recess between its ends, said insulator having an upper fluid admission port from its upper end to said recess, said insulator also having a lower uid conducting port from said recess to the lower end of the insulator, a lower positive electrode Vsection reciprocable in said lower port and having a valve head at its -upper end, said valve head being disposed insaid recess and having limited vertical movement therein, said lower port having radial grooves leading from its upper end and terminating. beyond the periphery of the valve head whereby said valve head may rest on the bottom of 'said recess without closing said lower port whenv said valve head is lowered, said valve head being shaped to close said upperport when raised, means for conducting current to said -lower elec' trode section including an upper electrode, sectic-n having a binding post, and a shell in which said insulator is mounted, said shell having a negative electrode spaced laterally from the lower end portion of said lower electrode section, said insulator being transversely divided into sections which abut each other, said recess being formed in at least one of said insulator sections, said insulator sections having tightly vintermeshed ribs on their abutting surfaces.

2. A spark plug comprising a central insulator having an internal recess between its ends, said insulator having an upper fluid admission port from its upper end to said recess, said insulator also having a lowerA fluid conducting port from said recess to the lower end of the insulator, a lower positive electrode section reciprocable in said lower port and having a valve head at its upper end, said valve head being disposed in said recess and having limited vertical movement therein, said lower port having radial grooves leading from its upper end and terminating beyond the periphery of the valve head whereby said valve head may rest on the bottom or said recess without closing said lower port when said valve head is lowered, said valve head being shaped to close said upper port when raised, means for conducting current to said lower electrode section including an upper electrode section having a binding post, and a shell in which said insulator is mounted, said shell having a negative electrode spaced laterally from the lower end portion of said lower electrode section, said insulator being transversely divided into sections which abut each other, said recess being formed in at least one of said insulator sections, said insulator sections having tightly intermeshed concentric ribs on their abutting surfaces.

3. A spark plug comprising a central insulator having an internal recess between its ends,

therein, said lower port having radial grooves leading from its upper end and terminating beyond the periphery of the valve head whereby said valve head may rest on the bottom of said recess without closing said lower port when said valve head is lowered, said valve head being shaped to close said upper port when raised, means for conducting current to said lower electrode section including an upper electrode section having a binding post, and a shell in which said insulator is mounted, said shell having a negative electrode spaced laterally from the lower end portion of said lower electrode section, said insulator comprising an upper section having said recess and said upper port, and a lower section having said lower port, said upper and lower A insulator sections having tightly abutting inner ends, said insulator sections having tightly intermeshed concentric ribs on said abutting inner ends.

LLOYD MCKINSEY FIELD.

References Cited in the 1ile of this patent UNITED STATES PATENTS Number Name Date 1,319,318 Bain Oct. 21, 1919 1,466,316 Varone Aug. 28, 1923 1,985,192 OMarra Dec. 18, 1934 2,053,369 Jeiery Sept. 8, 1936 FOREIGN PATENTS Number Country Date 285,352 Great Britain Feb. 13, 1928 345,528 Great Britain Mar. 26, 1931 

